When it comes to semi-automatic and automatic filling machines, there are no real set rules by the industry and there are many shades of gray that exist between the claims of automatic and semi-automatic machines.
However, for the most part the main difference is that a semi-automatic machine is going to need someone to operate it, where an automatic machine will only need someone to make sure that it continues to work.
Typically, a semi-automatic machine will have an operator that counts the containers as they go in and then operating a foot switch in order to start a filling sequence that is timed.
An automatic filling machine will not need the operator. These machines are fairly self-controlling once they are started. The operators will only have to perform an occasional quality control check. An operator may also have to provide consumables such as caps and labels. Custom programming and PLCs for these machines are quite expensive, so those customers that have budget can purchase the same filler equipment that has simple controls such as the semi-auto. These machines will just need more attention by the operator.
Automatic machines may be inline fillers that are equipped with a sensor that will count the bottles before a nozzle bar will be lowered to a newer generation of filler that is equipped with more powerful and modern PLCs. These machines have the capability to control a high seed packing line, will display the tank levels, operate product valves and pumps, have mechanized adjustments and even offer maintenance and troubleshooting checklists. The newer, more modern machines will even sound an alarm when the label roll diameter is too small or if the container level becomes too low. The upfront cost of an automatic machine will save in operator labor over time.